The protoype of this circuit, built at the first amplifier builders class
after VSAC 97, left all in the room at its debut rather smitten,
particularly John Tucker, who currently uses this circuit as his front line amp on his
Exemplars.

The midrange is balanced, smooth, and very real. Bass articulation is phenominal,
you would never expect this sound from a puny 45. Top end? How bout -1dB at 46kHz,
and black as can be?

Downside? Well, its only 1.6 watts, so you better have some pretty
efficient speakers (although Kim Jenkins seems happy with this setup on Whamos).

And its not a forgiving circuit, if your front end sucks, youll know
it. This amp reveals a great deal of information.

Also, doing it right means it isnt a super cheap project. For best
performance youll want to use nickel core parallel feed output transformers, and
proper plate loading chokes. The choice of manufacturers for these items is pretty narrow
(said with a big grin). The name of this amp gives about 90% of the circuits
description. Note the use of an active load on the driver stage. This load is quite
similar to the one used in the Afterglow circuit, and in concert with the parallel feed
output arrangement, accounts for the amps superior speed and bass response.

You might try this load, with the proper adjustments as outlined in the note on
the next page, as a load for your other projects. Try it on the first stage of the 5963
output stage in George Wrights line amp, or on top of the mu follower in the S.E.X.
amp (put it in in place of the 20K resistor).

The 45 is running at a classic operating point, 250V plate-to-filament, with -50V
grid bias, yielding a 34mA current draw. Note that these voltages are translated up by the
plate voltage of the direct coupled driver stage, so actual measured voltage on the plate
of the 45 is more like 400V above ground. Man, I get all tingly just writing about this
amp.

Aside from the parafeed iron, most of the parts specd are fairly
non-critical in terms of manufac-ture. I changed Smoothplates spec for the PS
bleeders from metal film to carbon film, because Ive found they seem to hold up to
big startup voltage swings a little better.

Note that the power trans specs are the bare minimum required. Bigger may work
better.

Brooklyn BCP-15 plate loading chokes are available for $100 the pair, and
Magnequest EXO-45 (5K:8) and EXO-46 (5K:16) parallel feed output transformers are
available for $150 the pair with M6 steel laminations, and $250 the pair with Permalloy
(nickel) laminations. For a real treat, we also have a couple of pairs of the Permalloy
EXO-46s with pure silver secondaries and Teflon coated touched by God copper
primaries, for $650 the pair. Call 360-697-1936 to order any of these goodies.